In recent years, large-scale integrated circuits (LSI), which are integrally formed on one chip by connecting plural transistors, resistors and so on as an electric circuit, are frequently used as essential parts of computers and communication instruments. For this reason, the performance of the entire instrument is largely related to the performance of an LSI formed on a single chip, i.e. “a simplex LSI”. The enhanced performance of a simplex LSI can be achieved by increasing the degree of integration therein, namely, by the miniaturization of the elements thereof. The miniaturization of elements, for example in the case of the MOS field effect transistor (MOS transistor), can be achieved by shortening the gate length and thinning of the source and drain area regions.
A nonvolatile high density memory, such as a flash memory, as well as memories such as dynamic RAM, MRAM, PC-RAM Re-Ram and so on, LOGIC-LSI, SRAM, System LSI and others require a lower processing temperature as the miniaturization thereof progresses.